If you have a certain kind of asthma, your doctor may prescribe Fasenra.

Fasenra is a prescription medication used to treat severe eosinophilic asthma in adults and some children.

This drug should not be used in certain cases. To learn more, see the “What is the Fasenra injection used for?” section below.

Fasenra basics

Fasenra’s active drug is benralizumab. (An active drug is an ingredient that makes a medication work.) It’s a kind of biologic drug. A biologic is made from parts of living organisms.

Fasenra is not available in a biosimilar form. (Biosimilars are like generic drugs. But unlike generics, which are made for non-biologic drugs, biosimilars are made for biologic drugs.)

Fasenra is a liquid solution that you’ll receive as an injection under the skin. It’s available in two forms:

  • single-dose, prefilled syringes
  • single-dose, prefilled autoinjector pens

Keep reading for information about Fasenra, including the drug’s side effects, uses, and dosage, and more.

Like most drugs, Fasenra may cause mild or serious side effects. The lists below describe some of the more common side effects that Fasenra may cause. These lists don’t include all possible Fasenra injection side effects.

Keep in mind that side effects of a drug can depend on:

  • your age
  • other health conditions you have
  • other medications you take

Your doctor or pharmacist can tell you more about the potential side effects of Fasenra. They can also suggest ways to help reduce side effects.

Mild side effects

Here’s a short list of some of the mild side effects that Fasenra can cause. To learn about other mild side effects, talk with your doctor or pharmacist, or read Fasenra’s prescribing information.

Mild side effects of Fasenra that have been reported include:

Mild side effects of many drugs may go away within a few days to a couple of weeks. But if they become bothersome, talk with your doctor or pharmacist.

Serious side effects

Serious side effects from Fasenra can occur, but they aren’t common. If you have serious side effects from Fasenra, call your doctor right away. But if you think you’re having a medical emergency, you should call 911 or your local emergency number.

The only serious side effect reported in studies of Fasenra was allergic reaction. To learn more about this side effect, see “Allergic reaction” just below.

Allergic reaction

Some people may have an allergic reaction to Fasenra. But in studies of the drug, this side effect wasn’t common.

Symptoms of a mild allergic reaction can include:

A more severe allergic reaction is rare but possible. Symptoms of a severe allergic reaction can include swelling under your skin, usually in your eyelids, lips, hands, or feet. They can also include swelling of your tongue, mouth, or throat, which can cause trouble breathing.

Call your doctor right away if you have an allergic reaction to Fasenra. But if you think you’re having a medical emergency, call 911 or your local emergency number.

Fasenra is used to treat severe eosinophilic asthma in adults and in children ages 12 years and older.

Eosinophilic asthma results from a high level of white blood cells called eosinophils. These cells are part of your immune system. But with this condition, the cells mistakenly attack your body’s airways. This leads to swelling and damage, causing symptoms such as:

Symptoms typically worsen with higher levels of eosinophils in the body.

Fasenra works by attaching to eosinophils. It then sends signals to other cells in your body to destroy the eosinophils. This lowers the level of eosinophils in your body, helping to relieve symptoms.

Note: Fasenra should not be used to treat other conditions caused by a high level of eosinophils. And it should not be used to treat an asthma attack (sudden worsening of asthma symptoms). For this purpose, you should use a rescue inhaler, such as an albuterol inhaler (ProAir, Ventolin HFA), according to your doctor’s instructions.

Your doctor will recommend the dosage of Fasenra that’s right for you. Below are commonly used dosages, but always take the dosage your doctor prescribes.

Forms and strength

Fasenra is a liquid solution given as an injection under the skin. It’s available in two forms:

  • single-dose, prefilled syringes
  • single-dose, prefilled autoinjector pens

Both the Fasenra pens and syringes come in one strength: 30 milligrams (mg) per milliliter (mL) of solution (30 mg/mL).

Recommended dosages

The starting dose for Fasenra is one injection every 4 weeks for the first 12 weeks. Then your dosage will change to one dose every 8 weeks.

You may need to go to a doctor’s office to have your injections. Or you may be able to give yourself injections at home. For details, see the “How is Fasenra used?” section below.

Questions about Fasenra’s dosage

Below are some common questions about Fasenra’s dosage.

  • What if I miss a dose of Fasenra? Call your doctor if you miss a dose of Fasenra. They’ll advise you on what to do and help you adjust your dosing schedule, if needed.
  • Will I need to use Fasenra long term? You’ll likely use Fasenra long term, if you and your doctor agree that the drug is working well and is safe for you.
  • How long does Fasenra take to work? Fasenra begins working immediately after you receive a dose. But it may take several weeks before you notice improvement in your asthma symptoms.

Find answers to some commonly asked questions about Fasenra.

How does Fasenra work (what’s its mechanism of action)?

How a drug works is referred to as its “mechanism of action.”

Fasenra is used to treat severe eosinophilic asthma in adults and some children. (For more information, see the “What is the Fasenra injection used for?” section above.)

Fasenra works by attaching to certain white blood cells called eosinophils. When Fasenra binds to eosinophils, it sends signals to other cells in your body to destroy eosinophils. This lowers the level of eosinophils in your body, relieving symptoms of eosinophilic asthma.

Can Fasenra be used to treat nasal polyps?

Fasenra currently isn’t approved by the Food and Drug Administration (FDA) for treating nasal polyps. But one study found Fasenra effective for treating nasal polyps when used with corticosteroid nasal sprays.

The FDA is currently deciding whether to approve Fasenra for treating nasal polyps.

If you’re interested in learning more about treatments for nasal polyps, talk with your doctor.

What should I know about the Fasenra alternative drug Dupixent?

Fasenra and Dupixent (dupilumab) are both biologic medications prescribed to treat severe eosinophilic asthma in adults and some children. (Biologics are medications made from living cells rather than chemicals.)

Both are given as an injection under the skin.

But these drugs do have some differences as well. For example, Dupixent is also prescribed for treating certain conditions other than eosinophilic asthma.

To learn more about how Fasenra and Dupixent are alike and different, ask your doctor or pharmacist. They can also discuss with you the best treatment for your condition.

Does Fasenra cause any long-term side effects?

No, Fasenra isn’t known to cause long-term side effects. Long-term side effects weren’t reported in studies of the drug.

Long-term side effects are side effects that either:

  • start after you’ve taken a drug for a long time or after you end treatment, or
  • start during treatment and continue for a long time, possibly after treatment ends

Your doctor or pharmacist can answer any questions you may have about Fasenra and long-term side effects.

Is Fasenra used for COPD?

No, Fasenra isn’t used to treat chronic obstructive pulmonary disease (COPD).

One study didn’t find that the drug lowered the risk of COPD flare-ups. But another similar study is still gathering data about whether Fasenra might be an effective treatment for COPD.

If you’d like to learn about treatments for COPD, see this article, or talk with your doctor or pharmacist.

Both Fasenra and Nucala (mepolizumab) are prescribed to treat severe eosinophilic asthma in adults and some children.

Fasenra and Nucala are kinds of biologic medications, which means they’re made from living cells rather than chemicals. And they’re both given as an injection under the skin.

To learn more about how Fasenra and Nucala are alike and different, check out this side-by-side comparison. You can also ask your doctor if one of these drugs may be right for you.

Fasenra and Xolair are both prescribed to treat asthma. But the kinds of asthma they’re used to treat differ.

Both Fasenra and Xolair (omalizumab) are biologic medications, which means they’re made from living cells rather than chemicals. They’re both given as an injection under the skin. While they can cause similar side effects, different side effects are possible with each drug.

To find out more about Fasenra and Xolair, see this article. Your doctor can also tell you more about how these drugs are alike and different.

A healthcare professional can give you doses of Fasenra at a doctor’s office, or you may give yourself doses at home. You and your doctor will decide which option is best for you.

If you give yourself doses at home, be sure to follow your doctor’s instructions for the administration of Fasenra.

Using Fasenra

Fasenra is given as an injection under the skin.

If you’ll give yourself Fasenra doses at home, your doctor will prescribe Fasenra pens to you. These are prefilled with Fasenra, and each pen contains a single dose of the drug.

If a healthcare professional will give you Fasenra at a doctor’s office, they’ll use Fasenra prefilled syringes.

Accessible medication containers and labels

If you’re using Fasenra pens and you find it hard for you to read the label on your prescription, tell your doctor or pharmacist. Certain pharmacies may provide medication labels that:

  • have large print
  • use braille
  • contain a code you can scan with a smartphone to change the text into audio

Your doctor or pharmacist may be able to recommend a pharmacy that offers these options if your current pharmacy doesn’t.

Using Fasenra with other drugs

Fasenra is used together with other asthma medications to treat severe eosinophilic asthma.

In studies of Fasenra, people took the drug along with a high dose inhaled corticosteroid (ICS) and a long-acting beta agonist (LABA). These kinds of drugs are typically found together in inhalers. Examples include:

People also took other asthma medications besides an ICS/LABA inhaler in these studies. Your doctor will tell you more about the other asthma medications you’ll take together with Fasenra.

Note: You should not use Fasenra to treat an asthma attack (sudden worsening of asthma symptoms). Instead, you should use a rescue inhaler, such as an albuterol inhaler, according to your doctor’s instructions. And if your asthma symptoms ever feel life threatening, call 911 or seek emergency medical help.

Questions about using Fasenra

Below are some common questions about taking Fasenra.

  • Should I take Fasenra with food? You may receive Fasenra doses with or without food. Because the drug is given by injection, food won’t affect how well your body absorbs a dose. But some people who get nervous about injections find that eating helps calm their nerves.
  • Should I take Fasenra pens out of the refrigerator before giving myself a dose? Yes. Fasenra’s manufacturer recommends removing a Fasenra pen from the refrigerator about 30 minutes before giving a dose. This allows the medication to warm to room temperature. (A cold injection may be painful.)
Questions for your doctor

You may have questions about Fasenra and your treatment plan. It’s important to discuss all your concerns with your doctor.

Here are a few tips that might help guide your discussion:

  • Before your appointment, write down questions such as:
    • How will Fasenra affect my body, mood, or lifestyle?
  • Bring someone with you to your appointment if doing so will help you feel more comfortable.
  • If you don’t understand something related to your condition or treatment, ask your doctor to explain it to you.

Remember, your doctor and other healthcare professionals are available to help you. And they want you to get the best care possible. So don’t be afraid to ask questions or offer feedback on your treatment.

Certain factors may affect how well Fasenra works to treat asthma. These include your medical history and any medications you may take. Below are some of the important considerations to discuss with your doctor before you start receiving Fasenra.

Interactions

Taking a medication with certain vaccines, foods, and other things can affect how the medication works. These effects are called interactions.

There aren’t known interactions between Fasenra and other medications, foods, or herbal supplements.

But it’s still important to tell your doctor and pharmacist about other medications or herbal supplements you take. This can help avoid any potential drug interactions.

Warnings

Fasenra may not be right for you if you have certain medical conditions or other factors that affect your health. (Conditions or factors that could prevent your doctor from prescribing a medication are called contraindications.) Talk with your doctor about your health history before you take Fasenra. Factors to consider include those in the list below.

  • Parasitic infection. It’s not known whether treatment with Fasenra affects your body’s ability to fight a parasitic infection. If you have a parasitic infection, your doctor will likely treat this first before prescribing Fasenra.
  • Allergic reaction. If you’ve had an allergic reaction to Fasenra or any of its ingredients, your doctor will likely not prescribe the drug. Ask them what other medications are better options for you.

Fasenra and alcohol

There’s no known interaction between alcohol and Fasenra.

But alcohol may trigger asthma attacks for some people. If you have asthma, talk with your doctor about whether it’s safe for you to consume alcohol.

Pregnancy and breastfeeding

It’s not known whether it’s safe to take Fasenra while pregnant or breastfeeding.

If you receive Fasenra while pregnant, consider joining the Fasenra pregnancy registry. Pregnancy registries gather data on the safety of using medications such as Fasenra during pregnancy. This helps doctors in making recommendations about the care of their patients. To learn more about the registry, visit the website or call 877-311-8972.

If you’re pregnant or breastfeeding, or planning to become pregnant or breastfeed, talk with your doctor about the benefits and risks of Fasenra treatment during this time.

Costs of prescription drugs can vary depending on many factors. These factors include what your insurance plan covers and which pharmacy you use. To find current prices for Fasenra in your area, visit GoodRx.com.

If you have questions about how to pay for your prescription, talk with your doctor or pharmacist. A program called Fasenra 360 may also help lower the cost of the drug.

You can also check out this article to learn more about saving money on prescriptions.

Do not take more Fasenra than your doctor prescribes. Using more than this can lead to serious side effects.

What to do in case you take too much Fasenra

Call your doctor if you think you’ve taken too much Fasenra. You can also call 800-222-1222 to reach the American Association of Poison Control Centers, or use its online resource. But if you have severe symptoms, immediately call 911 or your local emergency number. Or, go to the nearest emergency room.

If you have severe eosinophilic asthma, your doctor may suggest you use Fasenra. Before you begin treatment, talk with your doctor and pharmacist about this. Asking questions can help you decide if the drug is a good treatment option for you. Here are a few examples to help get you started:

  • What should I know about treatments for my asthma besides Fasenra?
  • Will I take other medications for asthma together with Fasenra?
  • If I have side effects from Fasenra, is there a lower dose I can try?

To learn more about treatments for your condition, see this article:

To receive news about treatments and advice on managing your condition, consider signing up for Healthline’s allergies and asthma newsletter.

Q:

I’m giving myself Fasenra doses at home. Can you tell me about how I should store Fasenra pens?

Anonymous

A:

Follow these tips for storing your Fasenra pens at home:

  • Keep each Fasenra pen in its original carton until it’s time to give yourself a dose. Keeping Fasenra pens in their packaging helps protect the drug from light.
  • Do not freeze Fasenra pens or expose them to heat.
  • Store Fasenra pens in their original cartons in a refrigerator, at a temperature between 36°F to 46°F (2°C to 8°C).
  • If needed, you can keep Fasenra pens at a room temperature of up to 77°F (25°C) for as long as 14 days. You should safely discard any unused medication kept at room temperature for longer than this.
  • After giving yourself a dose, safely dispose of the Fasenra pen in a sharps container.

If you have additional questions about storage and disposal of Fasenra pens, ask your doctor or pharmacist.

The Healthline Pharmacist TeamAnswers represent the opinions of our medical experts. All content is strictly informational and should not be considered medical advice.

Disclaimer: Healthline has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.